An assessment of the Swedish grid and square-mesh codend in the English (Farn Deeps) Nephrops fishery

Abstract

A catch comparison method was used on a commercial vessel to assess the potential of a Swedish grid and square-mesh codend in reducing fish bycatch, in particular cod, in the Farn Deeps Nephrops fishery (England). A standard trawl with a diamond mesh codend, as currently used in the fishery, was compared against a trawl with a Swedish grid and against a trawl with a Swedish grid and square-mesh codend. The trawl with the grid and diamond mesh codend caught no cod of marketable size and fewer large whiting, plaice and haddock than the standard trawl. However, that trawl caught twice the number of small cod and more haddock (and more Nephrops), as did the standard trawl. The trawl with the grid and square-mesh codend caught less cod, haddock and whiting in all length classes, but Nephrops catches were around half that of the standard trawl. Using the grid meant a ∼75% reduction in revenue from bycaught fish and squid landings, and when combined with the square-mesh codend, a further reduction of 50% in revenue from Nephrops landings. The implications of these economic findings are evaluated.